1. Field of the Invention
The present invention relates to two novel polycyclic antitumor antibiotic compounds designated herein as albacarcin M and albacarcin V and to their preparation by fermentation of a new strain of Streptomyces albaduncus designated herein as Streptomyces albaduncus strain C38291 (ATCC 39151).
2. Description of the Prior Art
Isolation of the polycyclic antitumor agents named gilvocarcins V, M and E from the fermentation broth of Streptomyces anandii subsp. araffinosus strain C-22437 (ATCC 31431) is disclosed in J. Antibiotics 34: 1544-1555 (1981). The gilvocarcin antibiotics have the structures shown below: ##STR1##
As noted in the above-mentioned J. Antibiotics reference, gilvocarcins V and M were previously reported in J. Antibiotics 34: 266-275 (1981) as being isolated from the fermentation broth of Streptomyces gilvotanareus (NRRL 11382).
Gilvocarcin V and gilvocarcin M are the same as toromycin A and toromycin B, respectively, disclosed in Agric. Biol. Chem. 44: 1157-1163 (1980).
The antitumor antibiotic designated as ravidomycin Ia is disclosed in Can. J. Chem. 59: 3018-3020 (1981). Ravidomycin Ia, isolated from the fermentation broth of Streptomyces ravidus, has the structure ##STR2## Ravidomycin Ia thus possesses the same aglycone moiety as gilvocarcin V (toromycin A).
The antitumor antibiotic designated as virenomycin is disclosed in Antibiotiki 22: 963-967 (1977); see also Antibiotiki 23: 675-676 (1978), Soviet Journal of Bioorganic Chemistry 4(8): 798-802 (1978) and Encyclopedia of Antibiotics, Second Edition, J. S. Glasby, Ed., pg. 457, Wiley-Interscience, Chichester-New York-Brisbane-Toronto, 1979. Virenomycin is isolated from the fermentation broth of Streptomyces virens strains 3831 and 3931/183. While the sugar moiety has been identified (see Soviet Journal of Bioorganic Chem. reference above), the structure of the remaining portion has never been reported. Virenomycin, which has the same sugar moiety as the antibiotics of the present invention, is reported to have a "comparatively low antitumor activity and narrow spectrum" (Antibiotiki 22: 963-967 at 967, 1977).